package com.hmdp.service.impl;

import cn.hutool.core.bean.BeanUtil;
import cn.hutool.core.util.BooleanUtil;
import cn.hutool.core.util.StrUtil;
import com.baomidou.mybatisplus.extension.plugins.pagination.Page;
import com.hmdp.dto.Result;
import com.hmdp.dto.ScrollResult;
import com.hmdp.dto.UserDTO;
import com.hmdp.entity.Blog;
import com.hmdp.entity.Follow;
import com.hmdp.entity.User;
import com.hmdp.mapper.BlogMapper;
import com.hmdp.service.IBlogService;
import com.baomidou.mybatisplus.extension.service.impl.ServiceImpl;
import com.hmdp.service.IFollowService;
import com.hmdp.service.IUserService;
import com.hmdp.utils.SystemConstants;
import com.hmdp.utils.UserHolder;
import org.springframework.data.redis.core.StringRedisTemplate;
import org.springframework.data.redis.core.ZSetOperations;
import org.springframework.stereotype.Service;

import javax.annotation.Resource;
import java.util.ArrayList;
import java.util.Collections;
import java.util.List;
import java.util.Set;
import java.util.stream.Collectors;

/**
 * <p>
 *  服务实现类
 * </p>
 *
 * @author 虎哥
 * @since 2021-12-22
 */
@Service
public class BlogServiceImpl extends ServiceImpl<BlogMapper, Blog> implements IBlogService {

    @Resource
    private IUserService userService;

    @Resource
    private StringRedisTemplate stringRedisTemplate;

    @Resource
    private IFollowService followService;



    @Override
    public Result queryHotBlog(Integer current) {
         //根据用户查询
        Page<Blog> page =query()
                .orderByDesc("liked")
                .page(new Page<>(current, SystemConstants.MAX_PAGE_SIZE));
        // 获取当前页数据
        List<Blog> records = page.getRecords();
        // 查询用户
        records.forEach(blog ->{
            Long userId = blog.getUserId();
            User user = userService.getById(userId);
            blog.setName(user.getNickName());
            blog.setIcon(user.getIcon());
            this.isBlogLiked(blog);
        });
        return Result.ok(records);
    }

    @Override
    public Result queryBlogById(Long id) {

        //查询blog
        Blog blog=getById(id);
        if(blog==null)
        {

            return Result.fail("笔记不存在！");
        }
        //查新blog有关用户
        Long userId = blog.getUserId();

        
        //查询blog是否被点赞
        isBlogLiked(blog);

        User user=userService.getById(userId);

        blog.setName(user.getNickName());
        blog.setIcon(user.getIcon());


        return Result.ok(blog);
    }

    private void isBlogLiked(Blog blog) {

        //获取登录用户
        UserDTO user=UserHolder.getUser();
        if(user==null)
        {
            //用户未登录，无需查询是否点赞
            return;

        }


        Long userId = UserHolder.getUser().getId();

        //判断当前登录用户是否已经点赞(利用Redis的set集合作唯一性判断)

        String key="blog:liked:"+blog.getId();

        Double score = stringRedisTemplate.opsForZSet().score(key, userId.toString());


        blog.setIsLike(score!=null);




    }

    @Override
    public Result likeBlog(Long id) {

        //获取登录用户
        Long userId = UserHolder.getUser().getId();

        //判断当前登录用户是否已经点赞(利用Redis的set集合作唯一性判断)

        String key="blog:liked:"+id;

        Double score = stringRedisTemplate.opsForZSet().score(key, userId.toString());

        //是包装类，要用BooleanUtil工具类否则会出现空指针
        if(score==null)
        {
            //未点赞
            //数据库点赞加一
            boolean isSuccess = update().setSql("liked=liked+1").eq("id", id).update();
            //数据库更新成功后redis数据库加一
            if(isSuccess)
            {
                stringRedisTemplate.opsForZSet().add(key,userId.toString(),System.currentTimeMillis());
            }

        }
        else{
            //已点赞，数据库点赞数减一（即取消点赞）
            boolean isSuccess = update().setSql("liked=liked-1").eq("id", id).update();

           if(isSuccess)
           {
               //数据库更新成功后将该用户的set从redis中移除
               stringRedisTemplate.opsForZSet().remove(key,userId.toString());

           }

        }

        return Result.ok();
    }

    @Override
    public Result queryBlogLikes(Long id) {

        String key="blog:liked:"+id;

        //查询top5的点赞用户
        Set<String> top5 = stringRedisTemplate.opsForZSet().range(key, 0, 4);
        if(top5==null||top5.isEmpty())
        {
            return Result.ok(Collections.emptyList());
        }

        //解析出其中的用户id(map转换流)
        List<Long> ids = top5.stream().map(Long::valueOf).collect(Collectors.toList());

        String idStr = StrUtil.join(",", ids);

        //根据用户id查询用户(将user对象拷贝到UserDto中)
        List<UserDTO> userDTOS = userService.query()
                .in("id",ids)
                .last("order by field(id,"+idStr+") ").list()
                .stream()
                .map(user -> BeanUtil.copyProperties(user, UserDTO.class))
                .collect(Collectors.toList());


        return Result.ok(userDTOS);
    }

    @Override
    public Result saveBlog(Blog blog) {
         // 获取登录用户
        UserDTO user = UserHolder.getUser();
        blog.setUserId(user.getId());
        // 保存探店笔记
        boolean isSuccess = save(blog);
        if(!isSuccess)
        {
            return Result.fail("新增笔记失败！");
        }

        //查询笔记作者的所有粉丝select * from tb_follow where follow_user_id = userId
        List<Follow> follows = followService.query().eq("follow_user_id", user.getId()).list();

        //讲笔记id给所有粉丝
        for (Follow follow : follows) {

            //获取粉丝的id
            Long userId = follow.getUserId();

            //推送
            String key="feed:"+userId;
            stringRedisTemplate.opsForZSet().add(key,blog.getId().toString(),System.currentTimeMillis());

        }

        // 返回id
        return Result.ok(blog.getId());
    }

    @Override
    public Result queryBlogFollow(long max, Integer offset) {

        //获取当前用户
        Long userId=UserHolder.getUser().getId();;

        //查询收件箱
        String key="feed:"+userId;
        Set<ZSetOperations.TypedTuple<String>> typedTuples = stringRedisTemplate.opsForZSet()
                .reverseRangeByScoreWithScores(key, 0, max, offset, 2);


        //判断非空
       if(typedTuples==null||typedTuples.isEmpty())
       {
           return Result.ok();
       }
        //解析数据
        List<Long> ids=new ArrayList<>(typedTuples.size());

       long minTime=0;

       int os=1;

        for (ZSetOperations.TypedTuple<String> tuple : typedTuples) {

            //获取id
            ids.add(Long.valueOf(tuple.getValue()));

            //获取分数
            long time=tuple.getScore().longValue();

            if(time==minTime)
            {
                os++;
            }
            else
            {
                minTime=time;
                os=1;
            }

        }


        //根据id查询blog

        String idStr= StrUtil.join(",",ids);

        List<Blog> blogs = query()
                .in("id",ids)
                .last("order by field(id,"+idStr+") ").list();



        //封装并返回
        ScrollResult r=new ScrollResult();

        r.setList(blogs);
        r.setOffset(os);
        r.setMinTime(minTime);



        return Result.ok(r);
    }

}















